In many aircraft, control surfaces such as flaps, spoilers, or the like are positioned by motors. Brakes may be employed to hold the control surface at a desired position once driven to such position by a motor. The brakes are utilized to absorb aerodynamic forces fed back into the driving system by the reaction of air against the control surface.
A difficulty to be guarded against is the loss of power or inoperability of the brake release mechanism. In the case of an extended aircraft flap or the like, if the brake cannot be disengaged due to power failure or mechanical failure in its release mechanism, the flap extension can not be changed when it desirably might be returned to a neutral or some other position where it would not particularly affect the aerodynamic configuration of the aircraft.
Another difficulty of concern is the possibility of inoperability in the brake and the drive mechanism. Under such circumstances, the control surface, not being subject to positioning by the drive system, and not being braked by the brake mechanism would be free to oscillate on its mounting in response to aerodynamic forces imposed on it as the aircraft moves through the air. Such oscillation could conceivably affect the structural integrity of the associated components and/or create a measure of instability because of the uncontrolled constant change in the aerodynamic configuration of the aircraft.
Another difficulty resides in the fact that certain types of control surfaces are moved quite rapidly between various positions. Where one of the positions to which a control surface is being moved is at its limit of travel, inertial loads due to rapid movement of the control surface may undesirably stress various components of the system.
The present invention is directed to overcoming one or more of the above problems.